Understanding What Vitamins if You Don't Get Enough Sun: A Nutritional Guide

October 5, 2025 •

4 min read

An estimated 35% of American adults and 50% of the world's population may have a vitamin D deficiency, primarily due to insufficient sun exposure. If you are concerned about your intake, understanding what vitamins if you don't get enough sun is critical for your overall health.

Quick Summary

Limited sun exposure can cause a vitamin D deficiency, impacting bone health, immunity, and mood. Ensure adequate intake through vitamin D-rich foods, supplements, and lifestyle adjustments, especially during colder months or with high-risk factors.

Key Points

Primary Vitamin: The main vitamin you must monitor with insufficient sun exposure is vitamin D, as the body produces it via UVB rays.
Health Risks: Deficiency can lead to serious conditions like rickets in children and osteomalacia or osteoporosis in adults, causing bone and muscle weakness.
Food Sources: Dietary options include fatty fish (salmon, tuna), fortified products (milk, cereals), mushrooms, and egg yolks.
Supplements: Vitamin D3 supplements are generally more effective at raising and maintaining blood levels than vitamin D2, but both can work.
Individual Needs: Factors like latitude, skin tone, and diet influence your vitamin D needs, making supplements a reliable option for many, especially during winter.
Companionship: Ensure adequate calcium intake, as it works synergistically with vitamin D for bone health.

The sunshine vitamin and its significance

Vitamin D is often called the “sunshine vitamin” because the primary way our bodies produce it is through exposure to ultraviolet B (UVB) rays from sunlight. When sunlight hits the skin, it triggers a reaction that converts cholesterol into vitamin D3. This vital nutrient then plays a crucial role in regulating calcium and phosphorus absorption, which are essential for maintaining strong, healthy bones and teeth.

Beyond bone health, vitamin D influences a wide range of bodily functions, including immune response, neuromuscular function, and mood regulation. Therefore, a lack of sufficient sun exposure can have significant consequences, leading to potential deficiencies and related health issues. Factors such as living in northern latitudes, a darker skin tone (higher melanin reduces UV absorption), and consistently wearing protective clothing or sunscreen can all limit natural vitamin D production.

Health consequences of vitamin D deficiency

Without adequate vitamin D, the body's ability to absorb calcium and phosphorus is impaired. This can lead to a range of health problems, from mild symptoms to more severe conditions.

Skeletal health issues

Rickets: In children, severe vitamin D deficiency can cause rickets, a condition where bones become soft and weak, leading to skeletal deformities like bowed legs and delayed growth.
Osteomalacia: In adults, low vitamin D levels can result in osteomalacia, which causes softening of the bones, leading to bone pain, muscle weakness, and an increased risk of fractures.
Osteoporosis: In older adults, deficiency exacerbates osteoporosis, a condition characterized by reduced bone mineral density, making bones fragile and more susceptible to breaks.

Other health impacts

Weakened Immune System: Vitamin D helps the immune system fight off infections. Low levels have been linked to an increased susceptibility to illness.
Fatigue and Mood Changes: Chronic fatigue, bone and muscle pain, and mood changes such as depression are commonly reported symptoms of a vitamin D deficiency.
Increased Risk of Falls: Proximal muscle weakness caused by vitamin D deficiency increases the risk of falls, particularly in older adults.

Boosting your vitamin D intake: Food and supplements

Since relying solely on sunlight may not be feasible year-round or for all individuals, dietary sources and supplements become paramount. Few foods naturally contain significant vitamin D, but some are excellent sources, especially when fortified.

Dietary sources of vitamin D

Fatty Fish: Excellent natural sources include salmon, mackerel, trout, and sardines.
Cod Liver Oil: A highly concentrated source of vitamin D.
Mushrooms: Certain types, especially those exposed to UV light, can be a source of vitamin D2.
Fortified Foods: Many products are fortified to help boost intake. These include milk (dairy and plant-based), certain cereals, yogurts, and orange juice.
Egg Yolks: A modest source of vitamin D.

Supplements: D2 vs. D3

When diet and sunlight are insufficient, supplements can effectively raise vitamin D levels. Supplements come in two main forms: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). While both are effective, evidence suggests that vitamin D3 is more potent and increases blood levels to a greater extent.


Feature	Vitamin D2 (Ergocalciferol)	Vitamin D3 (Cholecalciferol)
Source	Produced from yeast or fungi exposed to UV light.	Produced from lanolin (sheep's wool) or lichen exposed to UV light.
Potency	Considered less potent and effective in raising blood levels.	More potent and increases blood levels for a longer period.
Vegan Option	Always vegan as it is plant-derived.	Vegan options are available, typically from lichen.
Absorption	Both forms are well absorbed by the body.	Both forms are well absorbed by the body.
Overweight Individuals	The potency difference between D2 and D3 may be negligible for those with a high BMI.	May not offer the same potency advantage in individuals with a high BMI compared to those with a lower BMI.

Practical steps for managing vitamin D intake

Get Tested: The best way to know if you need to increase your vitamin D is to have your levels checked by a healthcare provider, especially if you have risk factors for deficiency.
Embrace Fortified Foods: Incorporate fortified milk, cereal, and orange juice into your daily diet. This can help provide a consistent, baseline intake.
Consider a Supplement: Especially during winter months or if you have limited sun exposure, a daily vitamin D3 supplement is a reliable option. Discuss appropriate intake with a healthcare professional.
Smart Sun Exposure: A few minutes of sun exposure around midday can significantly boost vitamin D production. Factors like skin tone and location affect the needed time, so balance this with sun safety measures.
Mind Other Nutrients: Vitamin D works closely with other nutrients, most notably calcium, for bone health. Ensure your diet is rich in calcium from sources like dairy, leafy greens, and fortified foods. A multivitamin can help cover other nutritional bases if your diet is restricted.

Conclusion

For those who don't get enough sun, managing a healthy vitamin D level is a critical component of overall wellness. By incorporating vitamin D-rich and fortified foods into your diet and considering a D3 supplement, you can effectively counteract the health risks associated with insufficient sun exposure. Always consult a healthcare professional to determine the right strategy for your individual needs. For more details on recommended intakes and the science behind vitamin D, the National Institutes of Health (NIH) Office of Dietary Supplements website is a valuable resource.

Frequently Asked Questions

If you have limited sun exposure, you can increase your vitamin D intake through diet and supplementation. Incorporate foods like fatty fish, cod liver oil, and fortified products into your diet. Consider taking a vitamin D supplement, preferably D3, and consult a healthcare professional for guidance.

It is very difficult to meet vitamin D needs from food alone, as few foods naturally contain significant amounts. Most people, especially with limited sun exposure, will need to rely on fortified foods or supplements to maintain adequate levels.

Symptoms in adults can be subtle and include fatigue, bone and joint pain (especially in the back), bone loss, muscle weakness, and mood changes like depression.

While both D2 and D3 effectively raise vitamin D levels, evidence suggests that D3 is generally more potent and increases blood levels to a greater extent and for a longer duration. Most over-the-counter supplements contain D3.

Some of the best dietary sources include fatty fish like salmon and mackerel, cod liver oil, and fortified products such as milk, cereal, and orange juice.

Yes, your geographical location significantly impacts your ability to produce vitamin D from sunlight. People living far from the equator receive less intense UVB radiation, particularly during winter, and may need to rely more heavily on diet and supplements.

For those with limited sun exposure year-round, such as those who are housebound or always covered, taking a daily supplement is often recommended. Others might only need one during the autumn and winter months when sunlight is less effective.